Formula to display items that have more than one value selected in a custom multi select field

I need help with creating a search to display only items that have more than one value selected in a custom multi select field. Is that a possibility via a formula?

Thanks.

Try Below Formula

LENGTH({custitem25}) - LENGTH(REPLACE({custitem25},',', ''))

Note: If your Multiselect field value does't contains comma.

If comma not there in your multiselect Field then it is working fine